● Duval Mine Rd, Sahuarita [Pima Co], AZ USA [el. 882 m / 2893 ft] view location in Google Maps » ● 11/06/10 7:47AM sunny, air temp: 17°C / 62°F When I first arrived, this large M. pergandei nest was relatively quiet, with just a few workers active. That all changed dramatically however, when the direct rays of the morning sun hit the nest at about 7:45AM. At this point, with an air temperature of 18°C / 64°F, hundreds off eager foragers poured out of the nest entrance in a single, wide column. This image shows the differently-sized workers that are are produced by the colony as availability of resources fluctuates during the year. [scroll down for additional notes/references] ADDITIONAL NOTES/REFERENCES: ·Rissing, S.W. 1986. Annual Cycles in Worker Size of the Seed Harvesting Ant Veromessor pergandei (Hymenoptera: Formicidae). Behavioral Ecology and Sociobiology (1987) 20:117-124 - Pogolumina - Pogonomyrmex Harvester Ants of North America